Not Applicable
Not Applicable
The present invention pertains generally to devices used to aid persons who have difficulty lowering into, or rising from, a seated position and more particularly to a powered lift seat that is easily transportable from place to place.
Persons with muscle weakness often require assistance to raise themselves from a seated position, or to lower themselves into a seated position in a controlled manner in order to avoid injury.
Lift chairs which provide this function have been available to the public for some time, such as is described in U.S. Pat. No. 4,083,599 (Gaffney, Apr. 11, 1978). However, the lift chairs known in the art are heavy and have the disadvantage of not being portable, which restricts the person""s movements outside the care facility or private home.
Portable lift devices are available that typically utilize springs to assist the person in rising or seating such as described in U.S. Pat. No. 5,082,327 (Crisp, Jan. 21, 1992). However, these devices have the limitation of requiring some muscular effort by the user, since the springs can provide only approximately 80% of the required force to support the person.
Similarly, U.S. Pat. No. 5,333,931 (Weddendorf, Aug. 2, 1994) is portable but the seating surface, in the raised position, tilts the user forward into an awkward position which persons with limited leg strength cannot use. The forward tilt also forces the seat backward unless restrained. Additionally, U.S. Pat. No. 6,113,188 (Stewart, Sep. 5, 2000) describes a device which presents a more comfortable seating configuration when raised. However, it incorporates an air filled bellows which will depress some amount, depending on the user""s weight, resulting in vertical instability. Also, the lifting mechanism requires a motor driven air compressor, the combination of which is typically of low efficiency, such that battery life is limited and may be heavy to lift and carry.
Of particular concern to users with limited muscle strength is the process of transitioning from a standing position to sitting on the raised platform; and, conversely, achieving a standing position from being seated on the raised platform of the apparatus. Neither the lift chairs nor the lift seats known in the art present a configuration which is totally suitable for this purpose.
Accordingly, there exists a need for a lift seat that is lightweight, compact and portable which can support the entire weight of a typical user, and which is both convenient and comfortable for the user. The current invention fulfills that need as well as others and generally overcomes the deficiencies of lift seats and chairs know in the art.
The present invention is an apparatus that is a portable lift seat for use by persons who need assistance in rising from a seated position or lowering into a seated position. By way of example and not of limitation, the apparatus of the present invention comprises a seat base and a two-piece seat platform which are interconnected and stabilized by positioning levers; and a motorized lift mechanism which is powered by removable and rechargeable batteries, and which may be augmented by tension springs. The motorized lift mechanism is comprised of multiple lift links which stage the lifting effort.
Several advantages of this invention, as compared to the prior art, are:
(a) The seat platform is formed of two pieces, hinged together, such that the rear portion remains horizontal while the front portion tilts forward during the lift process. Thus the point of contact between the user and the seat, when the user engages the seat, is approximately in the center of the seat platform, and the user need not reposition himself/herself following the seating process, or in preparation for disengaging from the seat. This configuration also minimize the tendency of the seat to move backward during engagement or disengagement by the user.
(b) The multi-staged lifting mechanism reduces required motor torque, thereby reducing motor size and resulting in increased battery life and a reduction in overall seat size and weight.
(c) Lightweight non-metalic springs may be used to augment the lifting force, thereby further increasing battery life while retaining reduced seat weight and size.
The apparatus of the present invention is lightweight, compact and self-contained. The apparatus utilizes rechargeable batteries for the power source, so that it is extremely portable. It incorporates a unique lift mechanism that is very efficient, thereby achieving long battery life; and also a unique seat configuration that provides and effective lifting platform for persons with reduced muscle strength.
Further objects and advantages of the invention will be brought out in the following portions of the specification, wherein the detailed description is for the purpose of fully disclosing preferred embodiments of the invention without placing limitations thereon.